Network service provider architecture in communications network

ABSTRACT

An improved architecture in a circuit switched communications network is provided in which a plurality of network service provider devices, eg intelligent peripherals are arranged to provide network service data to a plurality of time division multiplex circuits and trunks by converting these circuits and trunks to streams of packets, and providing network service data packetized in a set of network service data packet streams to the circuit packet streams without incurring delays to the circuit packet streams. The circuit packet streams may be duplicated and forwarded to the network service provider devices without incurring delay to the ongoing through put packetized circuits, and similarly packet streams containing network service data may be superimposed into the circuit packet streams, without the requirement for the circuit packet streams to be switched to the network service provider devices. The architecture comprises a plurality of TDM interfaces, a plurality of conversion means for converting from time division multiplexed mode to a plurality of packet streams; a plurality of packet streams switching devices and a plurality of network service provider devices.

FIELD OF THE INVENTION

[0001] The present invention relates to the provision of networkservices, and particularly although not exclusively to the provision ofnetwork services in circuit switched communications networks.

BACKGROUND TO THE INVENTION

[0002] Prior art time division multiplexed (TDM) telephone systemsprovide network services to individual calls by internally redirectingthose calls within an exchange to one or more individual network serviceprovider equipment items which may be co-located in the exchange, eitherwithin a switch, or within a rack or row of racks associated with aswitch. Network service provider devices provide services to callspassing through an exchange. Such devices may include networkannouncers, intelligent peripheral devices, universal tone receivers(UTRs) and universal tone generators (UTGs). Network announcers maycomprise simple announcement devices for sending messages such as “allinternational lines are busy” or the like. Such machines havehistorically developed from simple analogue devices for playingpre-recorded messages, more recently to digital devices for playingpre-stored messages. A universal tone generator provides dial tones to acall, and a universal tone receiver detects tone dial digits from acall.

[0003] Referring to FIG. 1 herein, there is illustrated schematically ageneral architectural overview of a prior art exchange comprising aconventional prior art TDM switch 100, a network announcer device 101,an intelligent peripheral device 102, and a universal tonereceiver/universal tone generator (UTR/UTG) device 103. Typically,network service provider components 101-103 may be co-located with theTDM switch within an exchange building in an array of racks asillustrated schematically in FIG. 2 herein. A conventional circuitswitched TDM call comprises first and second channels between anoriginating source device, eg a first telephone device, and a receivingdestination device, eg a second telephone device. Each circuit carriestraffic data, eg voice or fax/modem traffic data in a first direction onthe first channel from the first device to the second device and in asecond direction on the second channel from the second device to thefirst device. A call on an incoming (originating) TDM circuit or trunkmay be received by TDM switch 100 at an input port 104 of the switch,routed through the switch via one or more network service providerdevices associated with the switch and routed through an output port 105of the switch. Network services are provided by network service modulescomprising for example the network announcer, intelligent peripheral, orUTR/UTG.

[0004] In the conventional network, such network services are requiredat many points in the network. For example in prior art legacy networks,when a number is dialed, parts of the number are echoed from exchange toexchange across the network. Each exchange in a path has to separatelyrecognize it's portion of the dialed number and route the call on thatbasis. This process incurs delays at every exchange the call passesthrough. In legacy networks, it is common that some types of serviceprovider for example the UTR/UTG are provided at each exchange in thenetwork, whilst other types of service provider eg the network announceror intelligent peripheral may appear only at specified places in thenetwork and not on every exchange.

[0005] In each case, in prior art legacy networks the network serviceprovider comprises a discrete card or rack of equipment within anexchange. The exchange, when it receives a call either directly from asubscriber or from an incoming trunk recognizes dialed digits or anoff-hook signal, and internally switches the call to an appropriateservice provider component. This incurs delays throughout the network.

[0006] Referring to FIG. 3 herein, there is illustrated components of anexchange which detect a call and connect the call to a UTR and UTG. As acall is built up from originating source to destination, when a phone300 goes off hook, a seize detect element 301 of a local exchange 302detects that the phone has gone off hook. This causes an electronicconnection of the call to a universal tone generator 303 which applies adial tone back to the call.

[0007] In the prior art switches, the whole call must be switchedentirely through the internal switch network. Each switch takes time tore-direct the call to the appropriate network service providercomponent. In practice, the physical media used to connect each rack andcomponent is electrical or optical cabling using T1/E1 or higher ratetrunks. Where higher rates are used there is an inefficiency inre-multiplexing the data to a higher rate and then de-multiplexing datawithin the relevant service provider function. Normally, the wholespeech path of a call has to be passed to the relevant service providedcomponent and that component then has to pass the speech path back tothe switching fabric of the switch for completing a path to the outgoingtrunk, thereby incurring delays at the switch in connecting a call tothe network service provider devices.

SUMMARY OF THE INVENTION

[0008] One object of the specific implementations of the presentinvention is to avoid the delays associated with switching of a completecall through an internal switching network when providing networkservices.

[0009] Another object of specific implementations of the presentinvention is to avoid rebuilding internal switch paths for provision ofnetwork services to a call.

[0010] According to one aspect of the present invention that is provideda circuit switched communications nodal architecture capable ofproviding a plurality of network services to a plurality of timedivision multiplexed channels, said architecture comprising:

[0011] a plurality of conversion means for converting a plurality ofsaid time division multiplex channels to a plurality of packet streamchannels;

[0012] a plurality of interface means for interfacing between saidplurality of time division multiplixed channels, and said plurality ofconversion means;

[0013] a plurality of switching means each capable of switching saidpacket stream channels over a plurality of through connections throughsaid switching means; and

[0014] a plurality of peripheral devices, each capable of providingnetwork service signals; wherein

[0015] each said peripheral device communicates with at least one saidthrough connected channel by means of at least one further connectingchannel connecting said through connected channel and said peripheraldevice.

[0016] The through connected channel preferably extends directly throughsaid switching means without being routed through a said peripheraldevice.

[0017] The connecting channel preferably comprises at least one packetstream passing between the through channel and said peripheral device.

[0018] The connecting channel preferably carries data duplicated fromsaid through connected channel, said duplicated data being transmittedto said peripheral device.

[0019] Traffic data carried on a said through channel may be replicatedand broadcast to a plurality of said peripheral devices.

[0020] A time division multiplexed circuit comprising first and secondchannels may be converted by said conversion means into first and secondpacket stream channels, and each of said first and second packet streamchannels maybe replicated to produce first and second replicated packetstream channels which are communicated to a said peripheral device.

[0021] A said peripheral device may comprise a network announcer device,a universal term receiver device, a universal term generator device, anintelligent peripheral device, or a like device capable of providingnetwork service data to a one or a plurality of communications circuitsextending across the circuit.

[0022] According to a second aspect of the present invention there isprovided a method of providing network services to a communicationscircuit between a source device and a destination device, said circuithaving a time division multiplexed channel portion, said methodcomprising the steps of:

[0023] converting said time division multiplexed channel portion of saidcircuit to at least one packet stream channel;

[0024] passing said packet stream channel through at least one switchfabric; and

[0025] providing a connecting channel between said through packet streamchannel and a network service provider device, for communicating databetween said packet stream channel and said network service providerdevice.

[0026] Said method preferably comprises the step of duplicating a streamof packets carried on said through packet stream channel; and

[0027] supplying said duplicated packets to said network provider devicevia said connecting channel.

[0028] Said method may further comprise the steps of;

[0029] generating service data at said service provider device;

[0030] incorporating said service data into a plurality of packets;

[0031] incorporating said packetized service data into a channel of saidcircuit.

[0032] Said method may comprise the steps of;

[0033] generating service data;

[0034] incorporating said service data into a plurality of packets;

[0035] sending said packetized service data over said connecting channelconnecting an end to end channel of said circuit between a source deviceand said destination device with a said network service provider device.

[0036] Said method may comprise the steps of;

[0037] replicating a set of data packets comprising said throughchannel; and

[0038] supplying said stream of replicated data packets to a saidnetwork service provider device.

[0039] According to a third aspect of the present invention there isprovided a method of providing services to a plurality of communicationscircuits carrying traffic data, each said circuit comprising a timedivision multiplexed portion and a packetised portion, said methodcomprising the steps of;

[0040] converting said traffic data from a time division multiplexedmode to a packetized mode;

[0041] inputting a stream of packets containing said traffic data to aswitching element;

[0042] transporting said packet stream across said switching elementover a direct channel between an input and an output of said switchingelement;

[0043] generating a service data packet stream containing service dataproviding a network service;

[0044] inputting said service data packet stream to said switch element;and

[0045] incorporating said service data packets into said packet streamcontaining service data.

[0046] The invention includes an exchange apparatus in a communicationsnetwork, said apparatus capable of providing network services to aplurality of communications circuits, said exchange apparatuscomprising;

[0047] a switch element; and

[0048] at least one network service provider device capable ofgenerating network service data,

[0049] wherein said switch element is capable of replicating a datacarried on said circuit and directing said replicated data to saidnetwork service provider device, and

[0050] said switching means is capable of incorporating service datagenerated by said service provider device into said communicationscircuit.

[0051] The exchange apparatus preferably further comprises conversionmeans capable of converting between a time division multiplexed signalchannel of a said communications circuit and a packet stream signalchannel of said communications circuit.

[0052] A said switch element preferably comprises a plurality of inputsand outputs, and is adapted to carry said communications circuitdirectly across said switch between a said input and a said output, saidservice data being incorporated into said communications circuit betweensaid input and said output.

[0053] A said switch element preferably has a plurality of inputs andoutputs, and is adapted to transfer said communications circuit betweena said input and a said output in the form of a stream of packetizedsignals, wherein said switch element operates to replicate the saidstream of packetized signals and route said replicated packetized streamto a said service provider device.

[0054] According to a fourth aspect of the present invention there isprovided a circuit switch communications network comprising:

[0055] a plurality of switch fabrics;

[0056] a plurality of network service provider devices;

[0057] a plurality of conversion means converting between a timedivision multiplex mode and a packet stream mode;

[0058] a time division multiplexed access network;

[0059] wherein said communications network is architecturally arrangedsuch that said plurality of switch fabrics are distributed at aplurality of geographically disparate sites;

[0060] said plurality of network service provider devices are arrangedamongst said plurality of geographically separated sites;

[0061] a plurality of end to end through circuits are created acrosssaid communications network each said through circuit having a timedivision multiplexed portion and a packet stream portion;

[0062] said plurality of conversion means operate to convert betweensaid time division multiplexed access portions and said packet streamportions; and

[0063] a said through circuit communicates with a said network serviceprovider device by means of a connecting channel between said throughcircuit and said network service provider device.

[0064] The invention includes a circuit switched communications networkcapable of providing a plurality of network services to a plurality oftime division multiplexed channels, said communications networkcomprising:

[0065] a plurality of conversion means for converting a plurality ofsaid time division multiplex channels to a plurality of packet streamchannels;

[0066] a plurality of interface means for interfacing between saidplurality of time division multiplexed channels, and said plurality ofconversion means;

[0067] a plurality of switching means each capable of switching saidpacket stream channels over a plurality of through connections throughsaid switching means; and

[0068] a plurality of peripheral devices, each capable of providingnetwork service signals; wherein

[0069] each said peripheral device communicates with at least one saidthrough connected channel by means of at least one further connectingchannel connecting said through connected channel and said peripheraldevice.

BRIEF DESCRIPTION OF THE DRAWINGS

[0070] For a better understanding of the invention and to show how thesame may be carried into effect, there will now be described by way ofexample only, specific embodiments, methods and processes according tothe present invention with reference to the accompanying drawings inwhich:

[0071]FIG. 4 illustrates schematically a portion of a generalizedcommunications network architecture according to a first specificimplementation of the present invention;

[0072]FIG. 5 illustrates schematically an exchange comprising aswitching element and a plurality of network service provider devices,according to a second specific implementation of the present invention;

[0073]FIG. 6 illustrates schematically a first mode of operation of theexchange architecture of FIG. 5 for providing a universal tone receiverservice to a call carried on a TDM circuit;

[0074]FIG. 7 illustrates schematically a second mode of operation of theexchange architecture of FIG. 5, for providing a universal tone receiverservice to a call on a TDM circuit;

[0075]FIG. 8 illustrates schematically a third mode of operation of theexchange architecture of FIG. 5 for providing a network announcementservice to a call carried on a TDM circuit or trunk;

[0076]FIG. 9 illustrates schematically a fourth mode of operation of theexchange architecture of FIG. 5 for providing a network service suppliedby an intelligent peripheral device to a TDM circuit;

[0077]FIG. 10 illustrates schematically process steps in a generalizedmethod of operation of the generalized network of FIG. 4 and exchangearchitecture of FIG. 5;

[0078]FIG. 11 illustrates schematically process steps for a generalmethod of operation of a network service provider device, for example anintelligent peripheral device located within the generalized networkarchitecture portion of FIG. 4, or the exchange architecture of FIG. 5;and

[0079]FIG. 12 illustrates a modification of the exchange architecture ofFIG. 5, in which a plurality of legacy network service provider devicesare each provided with a packet adaptation means, and an interfacebetween a time division multiplex mode and a packet adaptation means.

DETAILED DESCRIPTION OF THE BEST MODE FOR CARRYING OUT THE INVENTION

[0080] There will now be described by way of example the best modecontemplated by the inventors for carrying out the invention. In thefollowing description numerous specific details are set forth in orderto provide a thorough understanding of the present invention. It will beapparent however, to one skilled in the art, that the present inventionmay be practiced without limitation to these specific details. In otherinstances, well known methods and structures have not been described indetail so as not to unnecessarily obscure the present invention.

[0081] Referring to FIG. 4 herein, there is illustrated schematically aportion of a generalized communications network architecture accordingto a first specific implementation of the present invention. The networkarchitecture comprises a plurality of interconnected exchanges 400-404each having at least one switching device an access network comprising aplurality of time division multiplexed access circuits or channels 405,connected with each switching device; and a plurality of network serviceprovider devices 405-407 comprising for example one or a plurality ofnetwork announcer devices, one or a plurality of intelligent peripheraldevices, one or a plurality of universal tone receivers, and one or aplurality of universal tone generator devices. In the general case, eachof the switches may be located at a separate site, geographicallyseparated from other sites, and the network service provider devices maybe distributed across the network arbitrarily at any site, co-locatedwith the switches, or at their own specific sites. However, in the bestmode herein, in practice one or more switching devices located at eachof the exchanges are located on cards stored on shelves of racks, andthe network service provider devices are co-located with switch deviceson adjacent cards, in adjacent shelves or racks connected to a switch bya common backplane.

[0082] A plurality of end to end circuits extend across the networkbetween a plurality of source devices, eg telephones, faxes, modems, orthe like and a plurality of corresponding destination devices, egtelephones, faxes, modems or the like. Each circuit extends through apair of time division multiplexed access channels in the access networkon an originating side of a circuit, through at least one said switchingmeans, and through a pair of time division multiplexed access channelson a destination side of the circuit. Each pair of channels comprisingthe circuit is converted between a time division multiplexed mode and apacket stream mode between the source and destination devices. Circuitsare connected directly on an end to end basis between a correspondingsource and destination, without being routed through any of theperipheral network service provider devices, but are provided withnetwork services by the network service provider devices by means ofadditional connecting channels between the end to end through circuits,and one or a plurality of said peripheral network service providerdevices.

[0083] In the best mode specific implementation described herein, theswitches comprise asynchronous transfer modes (ATM devices) however, ingeneral, the invention encompasses implementations comprising any typeof switch capable of making circuit switched connections for transportof packets.

[0084] In this specification, by the term “packets” it is meant anycell, frame or packet of pre-defined or indeterminate length comprisinga header portion containing address information, and a data payloadportion containing data traffic. Examples of packets include ATM cells.The term “data traffic” includes data selected from the set: voice data,computer generated data, and video data.

[0085] Referring to FIG. 5 herein, there is illustrated schematically anexchange comprising an ATM switch with a plurality of associated networkservice provider devices arranged according to the architecture subjectof the specific implementation of the present invention. The exchangecomprises an ATM fabric 500; an ATM backplane to which the ATM switchfabric is connected (backplane not shown in FIG. 5); first and secondATM adaptation devices 501, 502; first and second time divisionmultiplex interfaces 503, 504 for interfacing a plurality of TDMcircuits and/or trunks of an access network with first and second ATMadaptation devices 501, 502 respectively; control signaling means 505for controlling connections across the ATM switch fabric 500; and aplurality of network service provider devices comprising for examplenetwork announcer 506; intelligent peripheral 507; universal tonereceiver 508; and universal tone generator 509. Network announcer device506 operates to generate network announcements upon input of ATM cellsdirected to the network announcer. Announcements can be madebi-directionally to a call, in either direction of the call, either toan originating call side or an outgoing call side depending upon thetype of announcement activated. The intelligent peripheral device 507may comprise a voice processing device. Intelligent peripheral 507operates to perform voice processing functionality and supply voiceprocessing functionality to either side of a call path. For example theintelligent peripheral may comprise specific features such as faxdemodulation and echo cancellation, in which simultaneous access to bothdirections of a speech path is required. For some functions of theintelligent peripheral, for example announcement playouts,uni-directional access to a call-path may be sufficient. Universal tonegenerator device 508 and universal tone receiver device 509 may bepooled resources operating to detect MF or DTMF tone-based signaling,and for generating tones. The implementation illustrated in FIG. 5comprises an example where the volume of traffic and types of trafficthrough an exchange justifies having a plurality of network serviceprovider devices on a same site, co-located in adjacent or same racks.However, in principle, ATM fabric 500 may be replaced by an ATM networkextending geographically over an unbounded distance.

[0086] An overview of operation of the network architecture illustratedin FIG. 5 now follows. It will be appreciated that the architecture iscapable of bi-directional operation, and incoming and outgoing calls maybe received and dispatched in either direction, between a source anddestination of a dialed call.

[0087] Incoming TDM calls in a first direction either from trunks, orfrom circuits are input at first TDM interface 503, and are converted toATM cell streams by first ATM adaptation device 501 as is known in theart. The ATM cells generated by first ATM adaptation device 501 areentered into conventional ATM fabric 500 which routes the cell streamsto second ATM adaptation device 502, where the cell stream isreconverted back to a TDM circuit or trunk, and communicated throughsecond TDM interface 504 onto an outgoing circuit or trunk. ATM fabric500 acts as a straight through switch connecting an incoming circuit ortrunk channel to an outgoing channel, and vice versa for the otherchannel of the circuit or trunk. Additionally, ATM fabric 500 canduplicate a said cell stream comprising a said channel, and direct it toa network service provider, and/or can substitute an ATM cell streamgenerated by a network service provider device for a cell streamcomprising a through a channel of a circuit or trunk., or can direct anATM cell stream to an appropriate network service provider which canprovide a service either uni-directionally or bi-directionally along thecircuit or trunk.

[0088] Although an ATM fabric is illustrated as a switching means inFIG. 5 as the best mode herein, in the general architecture disclosedherein, the switching means may comprise a general circuit switchednetwork capable of switching channels and circuits in the form of ofpacket streams. In general, an incoming call may be converted to apacket stream, eg a stream of ATM cells, diverted through a circuitswitched transport resource, capable of carrying packet streams, forexample ATM fabric 500 or alternatively an ATM network, to one or aplurality of network service provider devices 506-509 located eitheradjacent the ATM fabric, or alternatively anywhere in the ATM network,the ATM cells being redirected to second ATM adaptation 502, havingnetwork services added to the call, and outgoing through second TDMinterface 504.

[0089] In the best mode illustrated in FIG. 5, universal tone receiver508 may detect significant messaging from the originating source of thecall. Universal tone receiver 508 may be permanently provided to a callin either direction of the call to provide tone recognition foractivating specific dial tone activated services, for example in-bandtone activated tone services, such as “1471” services, whereby bydialing the digits 1471 a last dialed call may be announced to a caller.Universal tone generator 509 provides tones to the originating side ofthe call.

[0090] Referring to FIG. 6 herein there is illustrated schematicallyimplementation of a “T” connection of a call to a universal tonereceiver 605 via ATM fabric 600. The “T” connection to the universaltone receiver 605 is created in ATM by use of a multi-cast function. Inthe multi-cast function, the incoming trunk or circuit is input intofirst ATM adaptation 601 via first TDM interface 603, and enters ATMfabric 600 as a stream of 53 byte ATM cells and output to second ATMadaptation device 602 where the cell stream is adapted to a timedivision multiplex signal which is output via second TDM interface 604to a destination of the call. Simultaneously, the through-cell system iscopied to create a second cell stream and the second, copied stream ofATM cells is fed continuously to the universal tone receiver device 605.A virtual circuit is created between first ATM adaptation 601 and secondATM adaptation 602, and another virtual circuit is created between firstATM adaptation 601 and universal tone receiver 605. Universal tonereceiver device 605, which operates in ATM mode, monitors tone dialsignals carried within the ATM cell stream for pre-determined dial tonemessages, eg numbers dialed, on a continuous basis without interruptingthe passage of the call through the ATM fabric 600 between first andsecond TDM interfaces.

[0091] Referring to FIG. 7 herein, there is shown a secondimplementation of connection of a universal tone receiver to a call.

[0092] In this implementation, universal tone receiver 700 monitors acall on a circuit or a trunk in both directions, from source todestination and from destination to source. A first channel of a circuitconnection extends between first ATM adaptation 701, through ATM fabric702, in which an ATM cell stream comprising a channel of a first virtualcircuit is multicast, that is to say copied to create a first cellstream duplicated and sent over to second ATM adaptation 703 and touniversal tone receiver 700. Similarly, in the opposite direction of thevirtual circuit, a second channel extending between second ATMadaptation 703 and first ATM adaptation 701 is multicast, by duplicatinga second stream of ATM cells, and connecting the duplicated secondstream from second ATM adaptation 703 to universal tone receiver 700 inanother multicast operation. Using the second configuration shown inFIG. 7, communications which require recognition of dial tones in eitherdirection on a call, for example between two fax modems may be routed tothe universal tone receiver 700 without incurring a switching delay forswitching the complete call to the universal tone receiver, but rathercreation of a connection between each channel of a circuit and theuniversal tone receiver, in parallel with connections between incomingand outgoing ports of an ATM fabric, by means of duplicating an ATM cellstream within the ATM fabric may allow continuous monitoring of bothdirections of a call, without incurring any additional switching delayin switching the call to the universal tone receiver.

[0093] During specific phases of a call, tones may be received ondifferent through channels of the circuit supporting the call fromeither side of a call, that is to say either source or destination. Forinstance, from the call originating side a start of a fax call maycomprise a first set of tones in a first direction which are sent bothto the destination, and to the universal tone receiver by virtue ofcreation of a duplicated cell stream directed to the universal tonereceiver in addition to the cell stream directed to an output ATMadaptation device, and during another phase of the call, the exchangemay similarly monitor tones received from the other (destination) sideof the call. Such operation is significant in situations, for examplewhere the exchange itself applies bandwidth compression to voice calls,since the detection of fax modem tones on both sides of a call indicatesto the exchange that the call is a fax call, and voice compressioncannot be applied to that call, because the bandwidth applied by a faxdata call is greater than that required by a compressed voice call. Thiscompares with the equivalent situation in the prior art case, whereinmultiple calls would be set up at each exchange, such that at eachexchange the call is routed to a universal tone receiver and thenrerouted back to an outgoing part of the exchange, thereby incurring adelay in switching the call to the relevant universal tone receiver ateach exchange. By comparison, in the specific implementations of thebest modes of the present invention, a call between source anddestination is not routed through the universal tone receiver, but theuniversal tone receiver receives a copy of the cell stream(s) comprisingthe call, which terminates at the universal tone receiver, leaving thethrough cell stream(s) between source and destination unaffected.

[0094] Referring to FIG. 8 herein, there is illustrated schematically athird mode of operation of the exchange architecture illustrated in FIG.5, in which a network announcer device 800 outputs an announcementmessage in either direction of a call, either towards a source of thecall, or towards a destination of the call, replacing other trafficcarried on a corresponding channel of the call. The network announcementmessage is switched into either channel of the call to replace thetraffic data by the ATM fabric. In either case, the network announcementmessage comprises a short term temporary connection of ATM cellscarrying the network announcement data which replace through ATM cellstreams 801 or 802 between first ATM adaptation 803 and second ATM 804in the appropriate direction. Since the through ATM cell stream is notre-directed to the network announcer, there is no inherent delay insubstituting an ATM cell stream from the network announcer for the ATMcell stream carrying the data traffic between source and destination.

[0095] This compares with the prior art exchange architecture, in whichthe complete call would need to be switched through the networkannouncer in order to apply the network announcement to the call,thereby incurring a switching delay in switching the call to the networkannouncer. Further, on termination of the network announcement message,the circuit needs to be reconnected between source and destination fromthe network announcer, thereby incurring a further switching delay. Inthe present mode of operation of the present architecture, disclosedherein such switching delay is avoided.

[0096] Referring to FIG. 9 herein, there is illustrated schematicallyoperation of the exchange architecture of FIG. 5 for connecting a callwith an intelligent peripheral device 900. The intelligent peripheralmay have an ability to play announcements, perform telecom measurements,perform DTMF detection, handle fax demodulation/remodulation, and/orrecord and replay voice. To supply these functions, intelligentperipheral 900 may access both sides of a call, at first ATM adaptation901 and second ATM adaptation 902. The access to the two channels of acircuit supporting a call required by the intelligent peripheral 900depends upon the function which intelligent peripheral 900 supplies tothe call. For example, fax demodulation requires tones to be sent froman incoming call side as well as tones to be returned from an outgoingcall side in order to perform a full demodulation/remodulation task.Other functions such as voice play and record require both directions ofan incoming call to be routed to an intelligent peripheral 900. Acircuit comprising first and second through channels 903, 904 betweenfirst ATM adaptation 901 and second ATM adaptation 902 in eitherdirection, which are carried by corresponding respective first andsecond ATM cell streams across ATM fabric 905 are accessed by means ofswitching either a first generated ATM cell stream generated byintelligent peripheral 900 in a first through direction between inputand output through ports of the ATM fabric, or by switching a secondgenerated ATM cell stream in a second through direction. First cellstream between first ATM adaptation 901 and second ATM adaptation 902 ina first direction may be copied and the copy cell stream routed tointelligent peripheral 900. Similarly, second through cell streamadaptation 902 and first ATM adaptation 901 may be copied and routed tointelligent peripheral 900 without incurring any switching delay to thesecond through ATM cell stream. Similarly intelligent peripheral 900 maysubstitute an ATM cell stream carrying a service for first or secondthrough ATM cell streams via first and second cell stream switches 907,908 respectively, in either direction of the call. Multicasting of ATMcell streams, or substitution of ATM cell streams for connecting tointelligent peripheral 900 incurs lower delay than in a correspondingprior art case, in which a complete call is switched to an intelligentperipheral device.

[0097] Similarly, substitution of an ATM cell stream generated byintelligent peripheral 900 may be carried out in ATM fabric 905 withoutincurring switching delay to either first or second through cellstreams. Intelligent peripheral devices may supply services such asvoice mail, wherein after a predetermined number of rings, anintelligent peripheral intersects a call and provides a voice messagegiving information as to the whereabouts of an individual and then givesan opportunity for recording of a message.

[0098] Referring to FIG. 10 herein, there is illustrated schematicallyprocess steps of a generalized method of operation of the networkarchitecture of FIG. 4, and the exchange architecture of FIG. 5. Theprocess steps operate in real time on a continuous basis for eachchannel of a pluarlity of circuits and/or trunks across the network orexchange. In step 1000, a plurality of time division multiplex circuitsor trunks carrying traffic data are interfaced, using TDM interfacemeans to an ATM adaptation device operating an ATM adaptation layer forconversion of time division multiplex signals to data payloads of aplurality of packets or cells, eg ATM cells, resulting in a convertedstream of packets in step 1001. A plurality of streams of packets areinput into a packet switch element in step 1002. Within the packetstream switch element, one or a plurality of packet streams may beduplicated, by copying the packets to provide a duplicate, parallelpacket stream. The duplicate packet stream is directed to a networkservice provider device on a continuous basis in step 1004, withoutincurring any delay to the original packet stream, which passes throughthe packet switch element. The packet switch element may comprise apacket switching fabric, eg a ATM switch fabric, or a plurality ofpacket switching elements, eg a complete ATM network.

[0099] Referring to FIG. 11 herein, there is illustrated schematicallyprocess steps for a generalized method of operation of a network serviceprovider device within the architectures of FIGS. 4 and/or 5. Thegeneralized method of operation of FIG. 11 applies to a network serviceprovider which is capable of handling data traffic arriving in the formof a packet stream, and for a network service provider device whichgenerates service data which is output from the network service providerdevice in a packet stream. In step 1100, the network service providermay receive a duplicated packet stream from a switch fabric containingtraffic data of a circuit and/or trunk. A plurality of packet streamsmay be received, one packet stream per channel of each circuit. In step1101, the packet payloads containing the data traffic may be storedinternally in the network service provider device, and in the case of anetwork service provider device which detects tones, the data payloadsof the packet streams are analyzed and tone data is detected from thetraffic data in step 1102. Tones may be analyzed in step 1103, and thenetwork service provider generates service data in response to andcorresponding to a pre-determined set of service provision rules storedinternally in the network service provider in step 1103. The servicedata provided by the network service provider device is packetized instep 1104 into a packet stream which is issued from the network serviceprovider device into the switch element in step 1105, whereupon it isswitched into a corresponding packet stream passing through the switchfabric in step 1105. Switching of the packet stream containing networkservice data into the appropriate circuit channel packet stream occurswithout switching the circuit channel stream through the network serviceprovider device, thereby avoiding a switching delay which wouldotherwise be incurred through circuit channel packet stream to thenetwork service device.

[0100] Referring to FIG. 12 herein, there is illustrated schematicallyan alternative architecture for an exchange, in which a plurality oftime division multiplex circuits and/or trunks pass through a switchfabric capable of handling a plurality of packet streams and areprovided with network services from a plurality of legacy networkservice provider devices 1200-1203, eg a universal tone receiver, auniversal tone generator, a network announcer, and/or one or moreintelligent peripheral devices. The network service provider devices maycomprise legacy equipment operating to accept time division multiplexcircuits or trunks. The exchange architecture comprises the packetswitch fabric 1204; an input TDM interface 1205; a first conversionmeans 1206 for converting TDM circuit channels to packet streams; asecond conversion means 1207 for converting between packet streams andTDM circuits and trunks; a second interface means 1208 for interfacingbetween second conversion means and a plurality of TDM circuits and/ortrunks; a control means 1209 for controlling the conversion means andswitch fabrics; and each network service provider device 1200-1203 beingsupplied with a corresponding respective TDM-packet stream convertordevice 1210-1213, and each conversion device associated with a networkservice provider being provided with a TDM-packet stream interface1214-1217.

[0101] General operation of the embodiment illustrated in FIG. 12 issimilar to that previously described herein, except a packet streamentering and exiting from the packet switch fabric 1200 to anappropriate network service provider device 1201-1204 undergoesre-conversion from a packet steam, via a said TDM-packet streaminterface, before entering legacy network service provider device1201-1204 operating to provide network service data in time divisionmultiplex format, which is then output back through the appropriatecorresponding respective TDM interface and conversion means into thepacket switch element 1200 for addition to the plurality of throughpacket streams passing through the packet stream switching fabric 1200similarly as hereinabove described.

1. A circuit switched communications nodal architecture capable ofproviding a plurality of network services to a plurality of timedivision multiplexed channels, said communications architecturecomprising: a plurality of conversion means for converting a pluralityof said time division multiplex channels to a plurality of packet streamchannels; a plurality of interface means for interfacing between saidplurality of time division multiplixed channels, and said plurality ofconversion means; a plurality of switching means each capable ofswitching said packet stream channels over a plurality of throughconnections through said switching means; and a plurality of peripheraldevices, each capable of providing network service signals; wherein eachsaid peripheral device communicates with at least one said throughconnected channel by means of at least one further connecting channelconnecting said through connected channel and said peripheral device. 2.The architecture as claimed in claim 1, wherein a said through connectedchannel extends directly through said switching means without beingrouted through a said peripheral device.
 3. The architecture as claimedin claim 1, wherein a said connecting channel comprises at least onepacket stream passing between a said through channel and a saidperipheral device.
 4. The architecture as claimed in claim 1, wherein asaid connecting channel carries data duplicated from said throughconnected channel, said duplicate data being transmitted to a saidperipheral device.
 5. The architecture as claimed in claim 1, whereintraffic data carried on a said through channel is replicated andbroadcast to a plurality of said peripheral devices.
 6. The architectureas claimed in claim 1, wherein a time division multiplexed circuitcomprising first and second channels is converted by said conversionmeans into first and second packet stream channels, and each of saidfirst and second packet stream channels is replicated to produce firstand second replicated packet stream channels which are communicated to asaid peripheral device.
 7. The architecture as claimed in claim 1,wherein a said peripheral device comprises a network announcer device.8. The architecture as claimed in claim 1, wherein a said peripheraldevice comprises a universal tone receiver device.
 9. The architectureas claimed in claim 1, wherein a said peripheral device comprises auniversal tone generator device.
 10. The architecture as claimed inclaim 1, wherein a said peripheral device comprises an intelligentperipheral device.
 11. A method of providing network services to acommunications circuit between a source device and a destination device,said circuit having a time division multiplexed channel portion, saidmethod comprising the steps of: converting said time divisionmultiplexed channel portion of said circuit to at least one packetstream channel; passing said packet stream channel through at least oneswitch fabric; and providing a connecting channel between said throughpacket stream channel and a network service provider device, forcommunicating data between said packet stream channel and said networkservice provider device.
 12. The method as claimed in claim 11,comprising the step of duplicating a stream of packets carried on saidthrough packet stream channel; and supplying said duplicated packets tosaid network provider device via said connecting channel.
 13. The methodas claimed in claim 11, further comprising the steps of; generatingservice data at said service provider device; incorporating said servicedata into a plurality of packets; incorporating said packetized servicedata into a channel of said circuit.
 14. The method as claimed in claim11, comprising the steps of; generating service data; incorporating saidservice data into a plurality of packets; sending said packetizedservice data over said connecting channel connecting an end to endchannel of said circuit between a source device and said destinationdevice with a said network service provider device.
 15. The method asclaimed in claim 11, comprising the steps of; replicating a set of datapackets comprising said through channel; and supplying said stream ofreplicated data packets to a said network service provider device.
 16. Amethod of providing services to a plurality of communications circuitscarrying traffic data, each said circuit comprising a time divisionmultiplexed portion and a packetised portion, said method comprising thesteps of; converting said traffic data from a time division multiplexedmode to a packetized mode; inputting a stream of packets containing saidtraffic data to a switching element; transporting said packet streamacross said switching element over a direct channel between an input andan output of said switching element; generating a service data packetstream containing service data providing a network service; inputtingsaid service data packet stream to said switch element; andincorporating said service data packets into said packet streamcontaining service data.